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MongoDB Articles
Page 103 of 111
Is it possible to write to MongoDB console in JavaScript execution?
Yes, you can write to the MongoDB console during JavaScript execution using the print() method for strings and printjson() method for objects. These functions are built-in utilities in the MongoDB shell. Syntax print("yourString"); printjson(yourObjectName); Method 1: Using print() for Strings To display a simple string message on the console ? print("Welcome to MongoDB Console"); Welcome to MongoDB Console Method 2: Using printjson() for Objects First, create a sample object ? studentInformation = { "StudentName": "John", "StudentAge": ...
Read MoreClone a collection in MongoDB?
To clone a collection in MongoDB, use the forEach() method to iterate through documents and insert them into a new collection. This creates an exact copy with all documents and their _id values preserved. Syntax db.sourceCollection.find().forEach(function(doc) { db.targetCollection.insert(doc); }); Sample Data First, let's create a collection with sample documents ? db.studentInformation.insertMany([ {"StudentName": "Chris"}, {"StudentName": "Robert"}, {"StudentName": "James"} ]); { "acknowledged": true, "insertedIds": [ ...
Read MoreHow to get element with max id in MongoDB?
To get the element with the maximum _id in MongoDB, use the sort() method with descending order and limit(1) to retrieve only the document with the highest _id value. Syntax db.collection.find().sort({_id: -1}).limit(1); Sample Data db.getElementWithMaxIdDemo.insertMany([ {"Name": "John", "Age": 21}, {"Name": "Larry", "Age": 24}, {"Name": "David", "Age": 23}, {"Name": "Chris", "Age": 20}, {"Name": "Robert", "Age": 25} ]); { "acknowledged": true, "insertedIds": [ ...
Read MoreHow can I rename a collection in MongoDB?
To rename a collection in MongoDB, you can use the renameCollection() method. This method allows you to change the name of an existing collection to a new name within the same database. Syntax db.oldCollectionName.renameCollection('newCollectionName'); Sample Data Let us first list all the collections from database sample to see the available collections ? use sample; show collections; copyThisCollectionToSampleDatabaseDemo deleteDocuments deleteDocumentsDemo employee informationAboutDelete internalArraySizeDemo prettyDemo selectWhereInDemo sourceCollection updateInformation userInformation Example Now let's change collection name 'informationAboutDelete' to 'deleteSomeInformation' ? db.informationAboutDelete.renameCollection('deleteSomeInformation'); { "ok" : ...
Read MoreCheck the current number of connections to MongoDB?
To check the current number of connections to MongoDB, you can use the db.serverStatus().connections command. This returns detailed connection statistics including current, available, and total connections created. Syntax db.serverStatus().connections; Alternative syntax using a variable ? var connectionInfo = db.serverStatus(); connectionInfo.connections; Method 1: Direct Command The simplest way to check connection statistics ? db.serverStatus().connections; { "current" : 1, "available" : 999999, "totalCreated" : 1 } Method 2: Using a Variable Store the server status and access connection data ? var checkCurrentNumberOfConnections ...
Read MoreMongoDB Query for boolean field as "not true
You can use the $ne (not equal) operator to query for boolean fields that are "not true". This operator returns documents where the field value is either false or does not exist. Syntax db.collectionName.find({ fieldName: { $ne: true } }); Sample Data Let us create a collection with employee documents to demonstrate the query ? db.queryForBooleanFieldsDemo.insertMany([ { "EmployeeName": "Larry", "EmployeeAge": 24, "isOldEmployee": true }, { "EmployeeName": "Mike", "EmployeeAge": 20, "isOldEmployee": false }, { "EmployeeName": "Sam", "EmployeeAge": ...
Read MoreMongoDB Query to select records having a given key?
To select records having a given key, you can use the $exists operator. This operator checks whether a field exists in the document, regardless of its value. Syntax db.collectionName.find({ fieldName: { $exists: true } }); Sample Data Let's create a collection with sample documents to demonstrate the $exists operator ? db.selectRecordsHavingKeyDemo.insertMany([ {"StudentName": "John", "StudentAge": 21, "StudentMathMarks": 78}, {"StudentName": "Carol", "StudentMathMarks": 89}, {"StudentName": "Sam", "StudentAge": 26, "StudentMathMarks": 89}, {"StudentName": "Sam", "StudentMathMarks": 98} ]); { ...
Read MoreCommand to show the database currently being used in MongoDB?
The command to show the database currently used in MongoDB is the following − Syntax db; This command returns the name of the currently active database in your MongoDB session. Check Available Databases Let us first check how many databases are present. The query is as follows − show dbs; The following is the output displaying all the databases − admin 0.000GB config 0.000GB local 0.000GB sample 0.000GB sampleDemo 0.000GB studentSearch 0.000GB test 0.003GB Example 1: Check Current Database Now, we have the list ...
Read MoreHow to clear console in MongoDB?
To clear the console in MongoDB shell, you can use either a keyboard shortcut or the cls command. Both methods instantly clear the terminal display, giving you a clean workspace. Syntax Method 1: Keyboard Shortcut Ctrl + L Method 2: Command cls Method 1: Using Ctrl + L (Recommended) The fastest way to clear the MongoDB console is using the keyboard shortcut. Simply press Ctrl + L while in the MongoDB shell ? > use myDatabase ...
Read MoreHow to remove object from array in MongoDB?
You can use $pull operator to remove objects from an array in MongoDB. The $pull operator removes all array elements that match a specified query condition. Syntax db.collection.update( { "matchField": "value" }, { $pull: { "arrayField": { "field": "value" } } } ); Sample Data Let us create a collection with a document containing an array of objects ? db.removeObjectFromArrayDemo.insertOne({ "StudentName": "John", "StudentAcademicProjectDetails": [ { ...
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